This is only our second batch of beer, and sometime last night (I wasn't here) the airlock popped off our carboy and the beer foam spilled over the side of the carboy and all. I have no idea how long the rubber cap has been off, so I have no idea how long it was exposed to air, but is there a chance it could still be ok?

Should we just throw this out and consider it ruined?
Should we finish this batch and see if it's ok?

Chazthetic wrote:snip ... Should we just throw this out and consider it ruined? Should we finish this batch and see if it's ok?

YIKES!!! (Think of John Belushi in 'Animal House' when the movers dropped a case of booze.) NEVER throw out any hard earned homebrew until you've given it a chance -- at least not at THAT stage; heck, all you have to do is put a sanitized glass over the neck of the carboy until the foaming stops, and then replace the glass with a resanitized air lock, and then sample the beer with a thief before bottling. It is only when faced with the decision of whether to bottle or not that I will ever consider tossing a brew; I mean, if you're pretty sure it is infected at that point and not just some off flavor that time might fix, then there's no point in going to all of the time and trouble of bottling it.

As for your specific problem, unless you have a good amount of headspace in a carboy, don't use an airlock during the first day or two of fermentation; you can cram a sanitized plastic hose in the neck of the carboy and curve the hose down into a container of water, or you can do what I've done succesfully for about a dozen batches now -- and just invert a santized glass over the neck of the carboy. The glass is probably not as good as the hose because it does not provide an airtight seal; on the other hand, with a lot of krauesen (foam -- bubbles filled with CO2) in the headspace, you don't have much oxygen anyway. And if you plan to replace it with an airlock and let it sit for a couple of weeks (instead of a secondary) ... and are concerned with oxygen that has leaked around the glass, you can use a very small sauce pan to boil a tablespoon of sugar in a few of ounces of water and dump that into the beer when you replace the glass with an airlock.

Good luck with your beer. Chances are very good that it will be just fine. Aside from a little oxidation, some airborne bacteria might have settled on the krauesen as it was dropping (settling back down into the carboy and beer), but by then the alcohol content, sparcity of food, high yeast count, and antibacterial quality of the hops should still give it an excellent chance. Wait and see, and have a homebrew to relax.

Chazthetic wrote:snip ... I was surprised it happened because I was using a rubber stopper with a hose and sanitizer solution haha.

I'm assuming the hops basically clogged the neck of the car boy and slowly moved up from the expanding C02 until it popped off the rubber bung.

This is the second time it's foamed up over the top, so I think we need a bigger carboy! haha.

If you are using a rubber stopper along with a hose, then the hose is undoubedly too small in diameter -- probably about the same size as the tube on a conventional plastic airlock. If an airlock can clog, then so can a small diameter hose. When I suggested a hose, I meant the largest diameter that you can fit tightly into the neck of your carboy WITHOUT using a stopper.

No need to get a bigger carboy; just make smaller batches unless you don't mind wasting the beer that overflows from your fermenter. My carboys are just 5 gallon water bottles, and started out making 5 gallon batches and losing a half-gallon of beer. Now I just scale my recipes to target a 4.5 gallon batch, and that's what goes into the carboy. Lately I've been using the inverted glass over the neck instead of a hose, and it has been working great. I still get a small amount of overflow in some batches, but it is only minimum. My beer has been turning out great, too.